imposed new sanctions to punish russia for stirring up trouble in ukraine. seven russian government officials were banned from traveling to the u.s. and their u.s. assets were frozen. 17 russian companies have also had their assets frozen. in ukraine, the mayor of the second largest city there was shot today in an assassination attempt. it's not clear who's responsible for that. by our count, pro-russian militants have taken government buildings in at least a dozen towns in eastern ukraine. a team of observers sponsored by the u.n. is being held hostage in one of them, and holly williams spoke to the self- proclaimed mayor who's holding those observers. >> reporter: in slovyansk, pro- russian separatists have been parading their prisoners. colonel axel schneider and his team of european military observer have been held in the town since friday. these captured ukrainian soldiers are also in slovyansk and were shown off to journalists bound and bloody. this coal mining town of 100,000 is at the center of the trouble in eastern ukraine. and this is the face of